In general, a semiconductor device, a display device and a solar cell are fabricated through a depositing process where a thin film is formed on a substrate, a photolithographic process where a thin film is selectively exposed and shielded by a photosensitive material and an etching process where a thin film is selectively removed. Among the fabricating processes, the depositing process and the etching process are performed in a substrate processing apparatus having a chamber of an optimum vacuum state. In the substrate processing apparatus, a reaction gas is activated to have a plasma state and the fabricating process is performed using the plasma state reaction gas.
The substrate processing apparatus for the depositing process and the etching process may be classified into an inductively coupled plasma (ICP) type and a capacitively coupled plasma (CCP) type according to a method of generating the plasma. The ICP type may be used for a reactive ion etching (RIE) apparatus and a plasma enhanced chemical vapor deposition (PECVD) apparatus, and the CCP type may be used for a high density plasma (HDP) etching apparatus and a HDP deposition apparatus. The ICP type and the CCP type have their respective principles of generating the plasma and have their own advantages and disadvantages. Accordingly, the ICP type and the CCP type are selectively used as occasion demands.
FIG. 1 is an inductively coupled plasma type substrate processing apparatus according to the related art. In FIG. 1, a substrate processing apparatus 10 includes a chamber 12, an antenna 14, a gas supplying plate 16 and a substrate supporter 18. The chamber 12 includes a lid 12a and a body 12b and provides a reaction space isolated from an exterior for processing a substrate. The lid 12a may be formed of an insulating material capable of transmitting an induced electric field of the antenna 14 to an interior of the chamber 12.
The antenna 14 is disposed over and spaced apart from the lid 12a. The antenna 14 is connected to a radio frequency (RF) power supply 22 through a feeder line 20, and the RF power supply 22 supplies an RF power to the antenna 14. The antenna 14 includes first and second antennas 14a and 14b. In addition, the feeder line 20 includes first and second feeder lines 20a and 20b. The first antenna 14a is connected to the RF power supply 22 through the first feeder line 20a and a variable capacitor C, and the second antenna 14b is connected to the RF power supply 22 through the second feeder line 20b. Accordingly, the first and second antennas 14a and 14b are connected to the RF power supply 22 in parallel. Further, a matcher 24 for matching a load and a source impedance is formed between the antenna 14 and the RF power supply 22.
The gas supplying plate 16 is connected to a gas supplying pipe 26 and sprays a process gas through the gas supplying pipe 26 into the interior of the chamber 12. The substrate supporter 18 faces into the gas supplying plate 16 and a substrate 28 is disposed on the substrate supporter 18.
In addition, the substrate processing apparatus 10 further includes a gate (not shown) for transferring the substrate 28 into and/or from the chamber 12 and an exhaust 30 for outputting a reaction gas and a residual product from the chamber 12.
In the substrate processing apparatus 10, when the RF power is applied to the antenna 14, a time varying magnetic field of a horizontal direction is generated around the antenna 14 and an electric field of a vertical direction is induced by the time varying magnetic field. The induced electric field is transmitted into the chamber 12 and electrons in the chamber 12 are accelerated by the induced electric field. The accelerated electrons collide with a neutral gas to generate ions and radicals, i.e., a plasma, and the depositing and etching processes are performed using the plasma.
While the first antenna 14a is connected to the first feeder line 20a and the RF power supply 22 through a first incoming portion 40a disposed at a center of the lid 12a, the second antenna 14b is connected to the second feeder line 20b and the RF power supply 22 through a second incoming portion 40b disposed at a region separated from the center of the lid 12a. Since the second incoming portion 40b of the second antenna 14b deviates from and is spaced apart from the center of the lid 12a, the first and second antennas 14a and 14b are not symmetrically disposed with respect to the center of the lid 12a. As a result, the RF power supplied from the RF power supply 22 is not uniformly distributed to the first and second antennas 14a and 14b and the uniformity of plasma density in the chamber 12 is deteriorated.